This invention relates to well fluids and to the recovery of oil from oil-bearing earth formations. In accordance with one aspect, this invention relates to post primary oil recovery of such formations. In accordance with another aspect, this invention relates to the use of well fluids comprising water containing hydrogen peroxide and at least one fatty amine oxide as a secondary recovery method during waterflooding, as a tertiary recovery method after waterflooding, or after a polymer or surfactant flood. In another aspect, this invention relates to the recovery of hydrocarbons from subterranean formations by injection of aqueous solutions containing hydrogen peroxide and at least one fatty amine oxide.
In waterflooding oil-bearing earth formations, water is injected down an input well and into the formation. The water displaces oil from the formation toward a producing well through which the oil is recovered. Many additives have been proposed for use in the water to improve oil recovery. Some of these work well in specific formations. The characteristic of the operation of additives in flooding water, however, has been that although certain additives might improve oil recovery from some reservoirs, these same additives did not improve recovery from other formations. The present invention is directed to the utilization of aqueous compositions in post primary oil recovery operations leading to enhanced recovery of oil from an oil-bearing earth formation.
Accordingly, an object of this invention is to provide an additive system for use with well fluids to improve oil recovery.
Another object of this invention is to provide a method for recovering oil from a permeable solid material which is contacted with an aqueous system containing additives for enhanced oil recovery.
Other objects, aspects, as well as the several advantages of the invention will be apparent to those skilled in the art upon reading the specification and the appended claims.